1. Making Magnets Chapter 22

2. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. A magnetic object can be made into a magnet by: The Stroking Method The Electrical Method

3. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. The Stroking Method Also known as the Touch Method. A magnetic object is stroked many times in the same direction with a magnet.

4. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. The Stroking Method You will need: a magnet a magnetic object

5. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. Try picking up iron filings with a magnetic object, for example, an iron nail. 1 The iron filings do not cling to the nail.

6. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. Now, stroke the iron nail about 20 times with one pole of a bar magnet. Stroke with the same pole and always in the same direction! 2

7. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. Try picking up iron filings with the iron nail again. The iron filings cling to the nail! The iron nail has become a magnet. It has been magnetised! 3

8. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. The Electrical Method Magnets are made using electricity. Magnets made by this method are called electromagnets.

9. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. An electromagnet is made by coiling an electrical wire round a magnetic object, e.g. an iron nail many times. The ends of the wire are connected to a battery.

10. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. Danger! Never use electricity from the mains to make an electromagnet!

11. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. At a glance … A magnetic object can be made into a magnet by: The Stroking Method The Electrical Method

12. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. At a glance … The Stroking Method A magnetic object is stroked many times in the same direction with a magnet.

13. My Pals are Here! Science 3B © 2004 Marshall Cavendish International (Singapore) Private Limited You are reminded that under the Copyright Act, it is an offence to reproduce or copy any part of this presentation without permission from Marshall Cavendish International (Singapore) Private Limited. Marshall Cavendish International (Singapore) Private Limited. At a glance … The Electrical Method An electromagnet is made by coiling an electrical wire round a magnetic object many times. The ends of the wire are connected to a battery.